Phyllurus fimbriatus, Hoskin, 2023

Hoskin, Conrad J., 2023, A new species of Phyllurus leaf-tailed gecko (Lacertilia: Carphodactylidae) from Scawfell Island, mid-east Queensland, Australia, Zootaxa 5244 (3), pp. 233-243 : 235-241

Phyllurus fimbriatus sp. nov.

Scawfell Island Leaf-tailed Gecko

( Figures 2 , 3 )

Material examined. Holotype. QM J97578 , adult female, original tail, Scawfell Island (20.8743°S, 149.6102°E; 200 m a.s.l.), 18 November 2021, C. J. Hoskin, E. Carmichael & E. Evans; Figure 2 . Paratypes. QM J97576 , subadult female, original tail ; QM J97577 adult male, regenerated tail ; QM J97579 , adult female, regenerated tail; collection details same as holotype .

Diagnosis. Distinguished from congeners by the following characters: large size (SVL to 113 mm); obviously flared original and regenerated tail; rostral scale partially divided by a single groove; body and tail surfaces with small tubercles, with larger spinose tubercles largely restricted to margins of original tail; anterior-most white band on original tail V-shaped or notched, and spanning full width of tail; ventral surfaces immaculate.

Etymology. The species name fimbriatus is Latin for ‘fringed’, referring to the restriction of spines on the original tail to a fringe along the outer edge.

Measurements and scale counts. All measurements and scale counts for the holotype and paratypes are presented in Table 1 . Description of type series. SVL = average 101.7 mm (90.7–110.7). Proportions (average, followed by range in brackets): AG/SVL = 0.47 (0.45–0.48), FL/SVL = 0.20 (0.19–0.20), LHL/SVL = 0.23 (0.22–0.24), L1/SVL = 0.46 (0.44–0.48), L2/SVL = 0.53 (0.51–0.54), NL/SVL = 0.19 (0.19–0.20), NW/SVL = 0.11 (0.10–0.12), HL/SVL = 0.27 (0.27–0.28), HW/SVL = 0.22 (0.22–0.23), HD/SVL = 0.110 (0.107 –0.115), SL/SVL = 0.124 (0.118 –0.131), ED/ SVL = 0.061 (0.057 –0.064), TL/SVL (original) = 0.77 (0.76–0.78), TT/SVL (original) = 0.41 (0.41–0.42), TW/SVL (original) = 0.20 (0.18–0.21), TD/SVL (original) = 0.066 (0.059 –0.073), TL/SVL (regenerated) = 0.49 (0.47–0.50), TT/SVL (regenerated) = 0.24 (0.22–0.25), TW/SVL (regenerated) = 0.23 (0.21–0.25), TD/SVL (regenerated) = 0.079 (0.077 –0.082). Scale counts (average, followed by range in brackets): internasals = 6.8 (6–7), supralabials = 15.0 (14–16), infralabials = 14.5 (13–16), subdigital lamellae under 4 th finger = 16.3 (15–18), subdigital lamellae under 4 th toe = 19.0 (18–20). Head. Large, depressed, triangular; covered in very small granules with scattered larger, pale, conical tubercles on sides of head; top of snout and canthul region have fine granular scales and no enlarged tubercles; canthul region moderately steep, with a moderately defined bony ridge extending forward from upper anterior margin of each eye towards naris; skin of head co-ossified with skull; deep, vertical groove partially (20–50%) dividing rostral scale ( Table 1 ); rostral not in contact with nostril; 6–7 scales along the upper margin of rostral shield (i.e., internasals); first supralabial scale taller than wide, remaining supralabials broad and steadily decreasing in size; first infralabial scale taller than wide, remaining infralabials broad and steadily decreasing in size; granular scales of chin and throat homogenously minute granules, with the exception of larger scales along the edge of the mental and infralabials (particularly abutting infralabials 1–3); ear opening conspicuous, vertical, much less than half as large as eye. Neck. Fairly broad; covered in small granules that are intermixed with evenly scattered larger pale conical tubercles the sides and top. Body. Depressed, covered in small granules; flanks and back evenly covered in scattered, small, conical tubercles; those on the back and side evenly small and scattered (as for neck); all ventral surfaces (even under limbs) covered in even, smooth, fine granules, with no enlarged tubercles; single male has a large post-cloacal bulge, with conspicuous cloacal ‘spurs’, consisting of a cluster of white triangular scales, on the anterior-lateral margin; no pre-cloacal pores on any individuals; axilla deeply invaginated. Limbs. Long and very slender, covered in small granular scales and with scattered, small, pointed tubercles dorsally; lacking tubercles on ventral surface; digits strongly compressed distally; dorsal surface of hands, feet and digits without enlarged conical tubercles. Original tail ( Fig. 2 ). Anterior half flared and leaf-shaped, then tapers abruptly into a long attenuated tip (tip 54% of total tail length for both specimens; Table 1 ); flared section strongly flattened; distal section rounded, terminating with a minute, rounded, white ‘knob’; dorsal surface covered in minute granules, with sparsely scattered enlarged spinose tubercles; margin of flared portion of tail undulating, with the ‘peaks’ each having several obvious, large spinose tubercles, making the tail distinctly spiny on the edge but smooth on the top; ventral surface smooth with a mosaic of small rounded to square or hexagonal scales. Regenerated tail. Disc-like, rounded shape, with thin, tapering distal portion (tip 47% and 50% of total tail length in the two specimens; Table 1 ); dorsal and lateral surfaces of disc and attenuated portion covered in fine, pointed granules; small, rounded knob on the end; ventral surface covered in mosaic of block like scales. Colour pattern in spirit (e.g., Fig. 2 ). Dorsal base colour grey to tan, with irregular large dark brown blotches on neck and body, and smaller, dark brown blotches on head and limbs; dark blotches on neck and back connected to be arranged as irregular, dark, transverse bars; dark, longitudinal markings extend from above hips to base of tail; top of head and snout has less pattern but W-shaped mark across top of snout, connecting the anterior margin of the eyes; diffuse pale band from lower anterior margin of eye diagonally to midway along jaw, and more obvious similar pale band from lower posterior margin of eye diagonally to just behind jaw; white ‘spot’ (from cluster of minute tubercles) above the ear; all dorsal and lateral surface of neck, body and limbs covered in fine white flecks (that are generally the small conical tubercles); ventral surfaces of chin, throat, chest, abdomen and limbs fairly even cream colour, except for dark smudging under the knees, feet and hands; original tail has pale grey-brown background with extensive dark brown-black mottling, and white bands; the white bands consist of a band at the base of the flared portion that is distinctly V-shaped, and unbroken across the width of the tail, then a very thin white band three-quarters of the way along the flared portion, then a thick white band at the start of the attenuated section, then two white bands along the attenuated section, and a white tip at the end of the tail; underside of flared portion of original tail has a pale background, with heavy, dark brown flecked and scattered white spots; ventral surface of attenuated portion of original tail starting with V-shaped white marking, then dark brown and white corresponding to stripes on dorsal surface; dorsal surface of regenerated tail dark brown with a few irregular pale markings (QM J97579) or light brown background with fairly even dark mottling (QM J97577); ventral surfaces have a pale background that is heavily (QM J97579) or moderately covered in dark brown mottling (QM J97577). Colour pattern of type series in life. As above but base colour of body generally lighter (whitish grey), white and black markings (e.g., particularly on original tail) more contrasting, and ventral surfaces immaculate white.

Field data. Body size and maturity. SVL and tail data were collected from 23 individuals in the field, and these individuals were photographed to assess consistency in colour pattern traits. The majority of individuals observed were subadults of approximately 65 mm SVL. The smallest male with a pronounced post-cloacal bulge was 96 mm SVL. Individuals deemed male below that SVL (up to 85 mm) did not have a pronounced post-cloacal bulge. Male sexual maturity was therefore taken to be 96 mm SVL for the field data and, for the eight males that were this size and above, the average SVL was 102 mm (with a range between 96–105 mm; Table 1 ). The smallest female with eggs visible through the body wall of the abdomen was 103 mm SVL. None of the females inspected below that size (up to 96 mm SVL) had visible eggs, whereas six of the eight females inspected above 103 mm SVL had visible eggs. Female sexual maturity was therefore taken to be 103 mm SVL for the field data and, for the eight females that were this size and above, the average SVL was 109 mm (with a range between 103–113 mm; Table 1 ). Original tail (e.g., Figs 2 , 3A, 3B ). Of the 23 individuals for which tail status was recorded in the field, 8 (i.e., 35%) had an original tail. However, there was a clear relationship with body size: all 7 individuals <96 mm SVL had an original tail, whereas only 1 out of 16 individuals (i.e., 6%) that were 96 mm or longer had an original tail. Average TL/SVL for the 8 individuals with an original tail was 0.77 (range 0.74–0.81). Shape as described for type specimens. Tail colouration as described but with the following variation. The white band halfway along the flared portion varies from thin but distinct in some individuals to a single, central white dot in others. The white band at the end of the flared portion is often V-shaped, or sometimes a diagonal line, rather than straight and transverse. The degree of dark brown mottling on the flared portion of the tail varies from light to heavy. Regenerated tail (e.g., Figs 3C, 3D ). Average TL /SVL for three individuals that appeared to have a full regenerated tail was 0.53 (range 0.46–0.60). Shape as described for type specimens, but varying in the degree to which the tail has regenerated, with the attenuated portion appearing to get relatively longer with tail size. Colour also appears to vary as the tail regenerates, with freshly regenerating tails being almost black and those more fully regenerated being paler and more similar to the background colouration of the body. Colour pattern. As described for the type series, noting the following variation. Base colour varies from light grey to brown, giving some individuals a much darker appearance (e.g., Fig. 3C ). One individual ( Fig. 3D ) was obviously different in colour pattern, being an even, soft brown colour with four longitudinal lines of dark blotches down the vertebral zone and a dorsolateral line of enlarged, pale tubercles.

Comparisons. Phyllurus fimbriatus sp. nov. could only be confused with congeners. The obviously flared original and regenerated tail readily distinguishes it from the following congeners that have a cylindrical, tapering tail: P. caudiannulatus P. kabikabi , P. gulbaru and P. pinnaclensis . Phyllurus fimbriatus sp. nov. differs from congeners with flared tails in the following ways (comparative data from Bauer 1990; Couper et al. 1993, 2000; Couper & Hoskin 2013). The V-shaped anterior-most white band on the original tail separates it from all other species. Large body size (av. SVL 105 mm, max. 113 mm; including field measurements) readily separates it from P. championae (av. 62 mm, max. 81 mm), P. isis (av. 69 mm, max. 76 mm), P. ossa (av. 74 mm, max. 89 mm), P. platurus (av. 80 mm, max. 99 mm), partially from P. nepthys (av. 91 mm, max. 103 mm), but not from P. amnicola (av. 97 mm, max. 113 mm; including field data). Neck, body, and dorsal surface of original tail relatively smooth, versus moderately to extremely spinose in P. championae , P. ossa and P. nepthys . Single groove partially dividing the rostral scale separates it from P. championae (single groove completely divides rostral) and P. ossa (typically three, sometimes two, partial grooves). Further differs from P. isis and P. ossa in having 6 or 7 scales along posterior margin of rostral scale (i.e., internasals) ( P. isis 9–11; P. ossa 8–11).

Broadly, most similar to P. amnicola ( Figs 4A, 4B ) and P. nepthys ( Figs 4C, 4D ), due to large body size and partial division of rostral scale. Differs from P. amnicola in having a wider (HW/SVL = 0.217 –0.232 vs. 0.207 –0.214) and shorter head (HL/SVL = 0.266 –0.276 vs. 0.277 –0.291); a shorter neck (NL/SVL = 0.188 –0.203 vs. 0.207 – 0.233); a less flared original tail; a V-shaped, unbroken anterior-most white band on the original tail (vs. straight and usually not continuous); and by the restriction of prominent spines on the original tail to the outer margin (vs. prominent spines also on anterior one-third of the dorsal surface of the tail in P. amnicola ). Phyllurus fimbriatus sp. nov. differs from P. nepthys by larger body size (SVL av. 105 mm, max. 113 mm vs. av. 91 mm, max. 103 mm); more flared original and regenerated tail; V-shaped anterior-most white band on the original tail (vs. straight); much less spinose dorsal surfaces of head, body and limbs (vs. extremely spinose); spines restricted to margin of flared portion of original tail (vs. prominent spines over dorsal and marginal surfaces); no spines on regenerated tail (vs. covered in spines); and immaculate white ventral surfaces (vs. ventral surfaces ‘peppered’ with brown).

Distribution. Appears to be restricted to Scawfell Island, approximately 50 km north-east of Mackay in mideastern Queensland ( Fig. 1 ). On Scawfell Island, known from deeply-piled boulders in two gullies but other areas of similar habitat on the island have not been surveyed.

Habitat and habits. Deeply layered rock with associated rainforest vegetation. Both known sites consist of deeply-piled granite boulders in a gully ( Fig. 5 ). The boulders are covered in ferns (e.g., Asplenium ) and vines (e.g., Hoya ) and have a canopy of Ficus and other rainforest trees ( Fig. 5 ). Phyllurus fimbriatus sp. nov. was restricted to areas with deeply-piled boulders—surveys in adjacent areas, including other areas of rainforest vegetation along the gullies and slopes did not find the species. Individuals were found on rock surfaces at night, and presumably retreat deep among the boulders during the day.

Density was high within suitable habitat, with at least fifteen individuals found within approximately three hours search time at each of the two sites. During the survey period (16–19 th November 2021), at least half of all individuals found were subadults of small size (approximately 65 mm). Of 16 adults inspected in the hand, 8 were males and 8 were females. Six of the eight adult females had two large eggs visible through the skin on the body wall, and two had no eggs visible. For estimates of size at sexual maturity for each sex, and data on original versus regenerated tail status in subadults and adults, see the Field Data section above.

Other gecko species observed at the two sites were Amalosia rhombifer ( Gray, 1845) and Heteronotia binoei ( Gray, 1845) . The introduced Asian House Gecko ( Hemidactylus frenatus ) was seen on granite rocks and trees within 1 km of both sites.

Figures

FIGURE 1. Map showing the distributions of Phyllurus species and subspecies in mid-east Queensland.

FIGURE 2. Holotype of P. fimbriatus sp. nov. (QM J97578). Photos: (A) Edward Evans; (B) Conrad Hoskin.

FIGURE 3. Phyllurus fimbriatus sp. nov. in life: (A) adult female with original tail; (B) juvenile with original tail; (C) adult female with regenerated tail; (D) adult male of unusual colouration, with regenerated tail. Photos: Conrad Hoskin.

FIGURE 4. Phyllurus amnicola with original (A) and regenerated tail (B), and P. nepthys with original (C) and regenerated tail (D). Photos: (A, B) Conrad Hoskin; (C, D) Anders Zimny.

FIGURE 5. Habitat of P. fimbriatus sp. nov. on Scawfell Island. Photo: Conrad Hoskin.